Supremacy distribution in evolving networks

We study a supremacy distribution in evolving Barabasi-Albert networks. The supremacy $s_i$ of a node $i$ is defined as a total number of all nodes that are younger than $i$ and can be connected to it by a directed path. For a network with a characteristic parameter $m=1,2,3,...$ the supremacy of an individual node increases with the network age as $t^{(1+m)/2}$ in an appropriate scaling region. It follows that there is a relation $s(k) \sim k^{m+1}$ between a node degree $k$ and its supremacy $s$ and the supremacy distribution $P(s)$ scales as $s^{-1-2/(1+m)}$. Analytic calculations basing on a continuum theory of supremacy evolution and on a corresponding rate equation have been confirmed by numerical simulations.Comment: 4 pages, 4 figure

Interplay between network structure and self-organized criticality

We investigate, by numerical simulations, how the avalanche dynamics of the Bak-Tang-Wiesenfeld (BTW) sandpile model can induce emergence of scale-free (SF) networks and how this emerging structure affects dynamics of the system. We also discuss how the observed phenomenon can be used to explain evolution of scientific collaboration.Comment: 4 pages, 4 figure

Ribosome Rescue, Nearing the End

In eukaryotes, Dom34 is involved in the rescue of ribosomes that stall on mRNAs during protein synthesis. Using ribosome profiling, Guydosh and Green reveal that, in addition to rescue of ribosomes stalled on truncated mRNAs, Dom34 also recycles ribosomes that are unexpectedly found in the 3′ untranslated regions of many cellular mRNAs

Thermodynamic forces, flows, and Onsager coefficients in complex networks

We present Onsager formalism applied to random networks with arbitrary degree distribution. Using the well-known methods of non-equilibrium thermodynamics we identify thermodynamic forces and their conjugated flows induced in networks as a result of single node degree perturbation. The forces and the flows can be understood as a response of the system to events, such as random removal of nodes or intentional attacks on them. Finally, we show that cross effects (such as thermodiffusion, or thermoelectric phenomena), in which one force may not only give rise to its own corresponding flow, but to many other flows, can be observed also in complex networks.Comment: 4 pages, 2 figure

Universal scaling of distances in complex networks

Universal scaling of distances between vertices of Erdos-Renyi random graphs, scale-free Barabasi-Albert models, science collaboration networks, biological networks, Internet Autonomous Systems and public transport networks are observed. A mean distance between two nodes of degrees k_i and k_j equals to =A-B log(k_i k_j). The scaling is valid over several decades. A simple theory for the appearance of this scaling is presented. Parameters A and B depend on the mean value of a node degree _nn calculated for the nearest neighbors and on network clustering coefficients.Comment: 4 pages, 3 figures, 1 tabl

Kesesuaian Komposisi Gizi dan Klaim Kandungan Gizi pada Produk Mp-asi Bubuk Instan dan Biskuit

Complementary food for breastfeeding period is known as one of the nutrition source for children aged 6 – 24 months old. However, nutritional content of complementary good has not been confirmed with International and national standard, yet, nutrition problems in Indonesia. This research on processed complementary food, aimed to confirmnutritional content with standard and identify the most frequently-appeared nutritional claims. There were nine samples of processed complementary food in a format of instant powder and five samples in a format of biscuit representing mereks and categories were in scope of this research. Conformity of nutritional content obtained from information on the label, were compared with International standard (Codex Alimentarius- CAC/GL 8-1991) and Indonesian National Standard (SNI 2005). According to this research, 88 percent of nutritional compositions in instant powder were conformed to Codex Alimentarius standard, however only 31 percent in biscuit were conformed to this International standard. On the comparison with Indonesian National Standard, 94 percent of nutritional content in instant powder were conformed to the standard and 86 percent of nutritional compositions in biscuit were also conformed to standard. The most frequently-apperead nutritional claims in the processed complementary food in scope were iron, calcium, protein, dietary fibre, and vitamin A. Three from five nutrients were closely relevant with current nutrition problem in Indonesia namely aenemia, protein/chronic energy deficiency, and vitamin A deficiency

Phenols content and 2-D electrophoresis protein pattern: a promising tool to monitor Posidonia meadows health state

<p>Abstract</p> <p>Background</p> <p>The endemic seagrass <it>Posidonia oceanica </it>(L.) Delile colonizes soft bottoms producing highly productive meadows that play a crucial role in coastal ecosystems dynamics. Human activities and natural events are responsible for a widespread meadows regression; to date the identification of "diagnostic" tools to monitor conservation status is a critical issue. In this study the feasibility of a novel tool to evaluate ecological impacts on <it>Posidonia </it>meadows has been tested. Quantification of a putative stress indicator, <it>i.e</it>. phenols content, has been coupled to 2-D electrophoretic protein analysis of rhizome samples.</p> <p>Results</p> <p>The overall expression pattern from <it>Posidonia </it>rhizome was determined using a preliminary proteomic approach, 437 protein spots were characterized by p<it>I </it>and molecular weight. We found that protein expression differs in samples belonging to sites with high or low phenols: 22 unique protein spots are peculiar of "low phenols" and 27 other spots characterize "high phenols" samples.</p> <p>Conclusion</p> <p><it>Posidonia </it>showed phenols variations within the meadow, that probably reflect the heterogeneity of environmental pressures. In addition, comparison of the 2-D electrophoresis patterns allowed to highlight qualitative protein expression differences in response to these pressures. These differences may account for changes in metabolic/physiological pathways as adaptation to stress. A combined approach, based on phenols content determination and 2-D electrophoresis protein pattern, seems a promising tool to monitor <it>Posidonia </it>meadows health state.</p

Sustaining Electron Transfer Pathways Extends Biohybrid Photoelectrode Stability to Years

The exploitation of natural photosynthetic enzymes in semi-artificial devices constitutes an attractive and potentially sustainable route for the conversion of solar energy into electricity and solar fuels. However, the stability of photosynthetic proteins after incorporation in a biohybrid architecture typically limits the operational lifetime of biophotoelectrodes to a few hours. Here, we demonstrate ways to greatly enhance the stability of a mesoporous electrode coated with the RC-LH1 photoprotein from Rhodobacter sphaeroides. By preserving electron transfer pathways, we extended operation under continuous high-light to 33 days, and operation after storage to over two years. Coupled with large photocurrents that reached peak values of 4.6 mA cm−2, the optimized biophotoelectrode produced a cumulative output of 86 C cm−2, the largest reported performance to date. Our results demonstrate that the factor limiting stability is the architecture surrounding the photoprotein, and that biohybrid sensors and photovoltaic devices with operational lifetimes of years are feasible

Differential Effects of Thiopeptide and Orthosomycin Antibiotics on Translational GTPases

SummaryThe ribosome is a major target in the bacterial cell for antibiotics. Here, we dissect the effects that the thiopeptide antibiotics thiostrepton (ThS) and micrococcin (MiC) as well as the orthosomycin antibiotic evernimicin (Evn) have on translational GTPases. We demonstrate that, like ThS, MiC is a translocation inhibitor, and that the activation by MiC of the ribosome-dependent GTPase activity of EF-G is dependent on the presence of the ribosomal proteins L7/L12 as well as the G′ subdomain of EF-G. In contrast, Evn does not inhibit translocation but is a potent inhibitor of back-translocation as well as IF2-dependent 70S-initiation complex formation. Collectively, these results shed insight not only into fundamental aspects of translation but also into the unappreciated specificities of these classes of translational inhibitors